An outstanding feature of this surah is the contrasts with respect to the previous surah (Al Ma'un) and within itself. While surat Al Ma'un deals with the evil deeds of wicked people, this surah, which is the smallest in the Qur'an, deals with the biggest reward being given to our prophet, the best human being and the most deserving of it. This reward is Al Kawthar, the abundance of all kinds of good things including a river in Paradise which is described in a Hadith as having banks of gold, a bed of rubies and pearls, with its soil more fragrant than musk and its water sweeter than honey and whiter than snow. We pray that Allah makes us of the fortunate ones that will drink from it.
Notice how the heedlessness with respect to salah, the showing off, and the stinginess mentioned in surah Al Ma'un are contrasted with this surah commanding the prophet to establish salah sincerely for Allah and to sacrifice from his best and most prized possessions.
The last ayah was revealed when the prophet had just lost his son and his enemy referred to him as being cut off. It's ironic that the children of this and other enemies embraced Islam and joined the prophet's ever-growing family of believers.